This invention relates generally to the field of semiconductor devices and, more particularly, to a method and system for inspecting semiconductor wafers via remote microscopy.
A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. The following notice applies to the software and data as described below and in the drawing hereto: Copyright 1999, Micron Technology, Inc., All Rights Reserved.
Microscopes are used to visually analyze the structural results of semiconductor processing. Fine features of semiconductor devices, such as transistor gates having sub-micron dimensions, are not readily visible to the human eye. Therefore, high performance microscopes, including scanning electron microscopes (SEMs) and scanning tunneling microscopes (STMs), are used to make these features visible. Semiconductor process engineers can, therefore, view these features to more efficiently diagnose problems that exist in semiconductor processes.
Conventionally, the images produced by microscopes are present only on monitors located with the microscopes. See Lampso, B. W. and Redell, D. D. (1980), Experience with Processes and Monitors on Mesa, Communications of the AACM, Vol. 23, No. 2:105-117. Often, the microscopes are located in the clean room complex of a wafer fabrication facility in which semiconductor processing is performed. Thus, wafers can be inspected in the midst of semiconductor processing without their removal from the clean room complex. As a result, the wafers are less likely to be contaminated by undesired particles that exist in far greater quantity outside the clean room complex. However, because the microscopes are located within the clean room complex, process engineers must necessarily don clean room uniforms, or bunny suits, and enter the clean room complex to view the inspected wafers. This technique is particularly inefficient when the process engineers, who are not normally stationed in the clean room complex, are required to enter the clean room complex to view microscopy results.
To enhance the efficiency of wafer inspection by process engineers, the present invention provides for a method and apparatus for remote semiconductor microscopy whereby video signals are broadcast from one or more microscopes to remote viewers. In one embodiment, a live video signal is broadcast from the microscope over a network to personal computers located in the offices of process engineers. The office-based process engineers are provided real-time, or substantially real-time, views of a wafer, including peripheral views of the wafer outside cell array boundaries. The process engineer, in his office, can direct a technician, operating the microscope in the clean room complex, to display a desired cell region-of-interest with the microscope.
Further, multiple process engineers can simultaneously view the video signal from the microscope(s). As a result, the process engineers can analyze, in real-time, or substantially in real-time, the information provided by the video signals. In this way, the process engineers can more efficiently collaborate to solve process problems, or even develop new process techniques.
Therefore, it is a benefit of the present invention that it diminishes the time in which semiconductor microscopy is performed. It is a further benefit of the present invention that it permits multiple process engineers to simultaneously review microscope data in real-time, or near real-time.